BEIJING, CHINA—Paleoanthropologists re-examining stone tools from the Paleolithic site of Shuidonggou have found that the relatively sophisticated stone tools known as blades began to appear in northern China around34,000 to 38,000 years ago. That's about ten thousand years earlier than archaeologists assumed. The discovery shows that not only were people using diverse technologies in eastern Eurasia at this time, but that the cultural traits neccessary to make these blades moved quickly from Central Asia to China.